Through an analysis of the sixth chapter of Lambda we will try to reconstruct the main argument of it. In a first time it gets to the statement of the unmoved eternal substance and of the circular as the only continuous motion, once among the main attributes that constitute their definition are the precedence and eternity. In a second time, after a little “brachilogic” twist, as Oehler called it, where suddenly Aristotle goes from the eternal movement to the eternal mover, a characterization of the latter as being pure actuality is reached. Having said that, a point that we consider relevant to note at the end of our discussion is that one of the regularity of things, which is already announced in the latter part of the chapter and that, as well as dialogue with other places of the Corpus as On Heavens, On Generation and Corruption or Physics, heads us to consider the First Unmoved Mover as the only principle of universal movement and from whose continuity depends the continuity of movement.